## Image area

QPix provides a scrollable plug-in area for displaying disk-based images and 4D picture objects. The area includes a menu bar, a tools widget, and a zoom widget.

To add a QPix area to a form, create a plug-in area object and select _QPix from the popup menu in the properties window. After the area rectangle is created, choose Advanced... from the object properties palette to get to the area's Advanced Properties Dialog. This allows for codeless initial setup of the area; modifications can be done procedurally, by means of the commands described in this chapter.

Notes

- Offscreen buffers: QPix speeds up screen redraws by using offscreen buffers when displaying disk files. The memory occupied by offscreen buffers depends solely on pixel depth and image dimensions (the size of the image file is irrelevant), and they may require a lot of memory.
- When displaying a 4D picture, QPix allocates and maintains a copy of the picture data. If you are displaying large pictures, set the original 4D picture to null in order to preserve memory (pict := pict * 0). Another good idea is to pass local pict variables to QPix; local variables exist only within the scope of the calling method and they are automatically destroyed by 4D.

To manage the area use the following commands:

QPx_SetAreaStyle | Configures the visual appearance of a QPix plug-in area
QPx_GetAreaStyle | Returns the visual appearance configuration of a QPix plug-in area
QPx_SetAreaParts | Configures the visual parts of a scrollable QPix plug-in area
QPx_GetAreaParts | Returns the configuration of the visual parts of a scrollable QPix plug-in area
QPx_SetAreaTools | Configures the tools popup menu of a scrollable QPix plug-in area
QPx_GetAreaTools | Returns the configuration of the tools popup menu of a scrollable QPix plug-in area
QPx_SetAreaFlags | Configures various options of a QPix plug-in area
QPx_GetAreaFlags | Returns various configuration options of a QPix plug-in area
QPx_SetAreaBackgroundColor | Configures various options of a QPix plug-in area
QPx_GetAreaBackgroundColor | Configures various options of a QPix plug-in area
QPx_SetAreaScrollOffset | Changes the scroll offsets of a scrollable QPix plug-in area
QPx_GetAreaScrollOffset | Returns the scroll offsets of a scrollable QPix plug-in area
QPx_SetAreaCurrentTool | Changes the currently selected tool in a scrollable QPix plug-in area
QPx_GetAreaCurrentTool | Returns the currently selected tool in a scrollable QPix plug-in area
QPx_SetAreaZoomFactor | Changes the zoom factor of a scrollable QPix plug-in area
QPx_GetAreaZoomFactor | Returns the zoom factor of a scrollable QPix plug-in area
QPx_SetAreaSelection | Changes the selection rectangle in a scrollable QPix plug-in area
QPx_GetAreaSelection | Returns the selection rectangle of a scrollable QPix plug-in area
QPx_GetAreaCmdStatus | Returns the status of a QPix plug-in area command
QPx_DoAreaCommand | Executes a QPix plug-in area command
QPx_CountAreaPages | Returns the number of pages in the image currently being displayed
QPx_GetAreaPage | Returns the number of the page currently being displayed
QPx_SetAreaPage | Instructs the plug-in area to display a specific page
QPx_SetAreaImageFile | Displays an image file in a QPix area
QPx_GetAreaImageFile | Gets the image file being displayed in a QPix area
QPx_SetAreaPicture | Displays a 4D picture in a QPix area
QPx_GetAreaPicture | Gets the 4D picture being displayed in a QPix area
QPx_SetAreaImporter | Assigns a graphics importer instance to a QPix plug-in area
QPx_GetAreaImporter | Returns a reference to the graphic importer used by a QPix plug-in area
QPx_CropAreaImage | Crops the image in a QPix plug-in area at the current selection
QPx_RotateAreaImage | Rotates the image in a QPix plug-in area by a number of degrees
QPx_ResizeAreaImage | Resizes the image in a QPix plug-in area
QPx_FlipAreaImage | Flips the image in a QPix plug-in area horizontally, vertically or both
QPx_InvertAreaImage | Inverts the colors of the image in a QPix plug-in area
QPx_ExportAreaImage | Exports the image from a QPix plug-in area to an image file
QPx_FilterAreaImage | Applies a filter to the image in a QPix plug-in area
QPx_BrightnessContrastAreaImg | Applies the "Escape Brightness and Contrast" filter to the image in a QPix plug-in area
QPx_SharpenAreaImage | Applies the "Sharpen" filter to the image in a QPix plug-in area
QPx_BlurAreaImage | Applies the "Blur" filter to the image in a QPix plug-in area
QPx_RGBBalanceAreaImage | Applies the "RGB Balance" filter to the image in a QPix plug-in area
QPx_HSLBalanceAreaImage | Applies the "HSL Balance" filter to the image in a QPix plug-in area

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